<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button class="btn">中500w</button>
    <script>
        document.querySelector('.btn').addEventListener('click', () => {
            const p = new Promise((resolve,reject) => {
                setTimeout(() => {
                    let n = 1
                    if( n >= 1 ){
                        resolve()
                    }else{
                        reject()
                    }
                },1000)
            })
            p.then(() => {
                alert('成功')
            },
            () => {
                alert('失败')
            }
            )
        })
    </script>
</body>
</html>